Drafting instrument



June 1, 1943. J. T. IVY

DRAFTING INSTRUMENT Filed Aug. 29, 1942 2 Sheets-Sheet 1 $667 62 .22?INVENTOR I June 1, 1943. NY 2,320,603

DRAFTING INSTRUMENT Filed Aug. 29, 1942 2 Sheets-Sheet 2 all,

(/2662? Tfyy MENTOR Patented June 1,1943

' UNITED STATES PATENT OFFICE Jessie Tllvy, Seattle, Wash. I ApplicationAugust 29, No. 456,685 7 4 Claims.

My invention relates to the drawing or outlining of geometrical figuresoi! predetermined contours, and has among its objects and advantages theprovision of an improved drawing instrument for reproducing such figuresin variable proportions.

In the accompanying drawings:

Figure 1 is a face view of the instrument;

Figure 2 is a side view; I

Figure 3 is a top plan view with portions oi the supporting legs brokenaway;

Figure 4 is an enlarged sectional view along the line 4--4 of Figure 2;

Figure 5 is an'enlarged sectional view along the line 55 of Figure 2;

Figure 6 is a sectional view along the line 6-6 of Figure 3';

Figure '7 is a sectional view along the line 'l---'! of Figure 3; l I

figure 8 is a cross sectional view of a pattern element which guides theinstrument to draw a figure of predetermined contour;

xFig'ure 9 is a sectional view of an inscribing rod;

Figure 10 is a fragmentary view of an extension for the inscribing rod;

Figure 11 is a fragmentary sectional view of a leg extension; and

'Figure 12 is a sectional view of a diameter increasing sleeveinsertable over the inscribing rod for coaction with the pattern elementto reduce the size of the outline being inscribed;

In the embodiment selected for illustration, I make use of a head 16 towhich is secured three supporting legs i2, i4 and [6. These legs arearranged in diverging relationship and each in-. cludes a threaded shanki8 threaded into a bore 26 in the bottom face of the head 16. Each legis also provided with a fixation pin 22 at its lower end 'ior engagementwith the drawing surface 24 to support the instrument against accidentalshifting.

Depending from the cradle I6 is an inscriber rod 26 comprising sections28 and 36. Section 36 is provided with a threaded shank 32 threadedlyengageable in a threaded bore 34 in the section 26. To the lower end ofthe section 36 is connected a chuck 36 which carries the inscribingpoint 36 for engagement with the drawing surface 24. In Figure 9, thesection 36 is provided with a bore 46 within which is mounted acompression spring 42, one end of the spring abutting the bottom wall ofthe bore and the other end abutting a flange 44 on the inner end or asmall rod 46 to which the chuck 36 is connected. A

' contoured outlines.

Washer 46 is threaded into the lower end of the section 66 for slidablyguiding the rod 46. In cases where a relatively long inscriber rod isrequired, particularly when outlining large patterns, an extension rod66 is interposed in the inscribed rod 26. This extension rod includes ashank 62 threadedly engageable. in'the bore 24 and a threaded bore 64for connection with the.

shank l2.

The inscriber rod 26 is connected with the head i6 for universalmovement. A ball 66 is formed at the upper end of the section 26, whichball is rotatably housed in a tapered neck 66 formed on one end of asleeve 66 threaded into a bore 62 in the head i6.

. Head I6 is provided with a vertical T slot 64 within which is slidablmounted a correspond-- ingly shaped scale rule 66. The scale rule issupported at right angles to the drawing surface 24 and liessubstantially in the plane oi the supporting legs I2 and ,I4. Means foradiustably securing the scale rule 66 in selected. operating positionscomprises a screw 66 having a square head 16 lying in a correspondinglyshaped recess I2 in the head I6. The recess 12 is deeper than thethickness of the head 16 and is so arranged as to bring the rear face ofthe scale rule 66 into engagement with the head I6, so that the scalerule may be fixedly secured through tightening of the nut 14.

To the lower end of the scale rule 66 is secured a cradle 16 withinwhich is mounted a formed on the key 86 and extends into acorrespondingly shaped recess 92 in the pattern element 18. A taperedrecess 94 is formed on the peripheral face of the pattern element 18diametrically opposite the recess 62 for the reception of the taperedend 96 of a screw 98. Thus the key 86- restrains the pattern element"from accidental rotation, while the screw 98 clamps the pattern elementin a fixed position between the two pointed ends 66 and 66.

On the flat wall I66 01' the cradle 16 is sea scale plate I02 also boredIul the pass ing of the shaft 82. A pointer I is keyed to the shaft 02and is held on the shaft against the plate I02 by a head I06 formed on ascrew I08 threaded into the shaft '2. A knob llil comprising a nut ismounted ona screw 2 extending through a slot I ll in the scale plateI02, which slot is concentrically arranged with respect to the axis ofthe shaft 22. The wall lllii is provided with a curved groove H8 foraccommodating the head Ill on the screw 2. Thus the pointer I may berotated about the axis of the shaft 82, and the scale plate I02 isprovided with a scale I across which the end of the pointer I04 sweepsto indicate the various angular positions of the pattern element II. Thezero position of the scale is indicated at I22, so that the patternelement ll will lie in a horizontal plane in parallelism with thedrawing surface 2 when the pointer I registers with the portions of theoutlines when employing the zero position on the scale I20. Since thekey l6 restrains the pattern element from rotation relatively to theshaft .2, rotation of the pointer I imparts corresponding rotation tothe pattern element.

On the front face of the scale rule 66 is provided two scales I24 andI26 respectively associated with pointers I28 and I30 formed on the headIII.

In operation, a series of pattern elements It I.

is employed, each pattern element having an opening of predeterminedcontour. Inreproducing geometrical contours lying in a plane parallelingthe drawing surface 24, the pointer IN is moved to zero position andfirmly latched by tightening the head or nut H0, When drawing thepattern, the instrument is held firmly by placing one hand on the headIt and grasping the rod 48 and lifting the chuck end off the drawingsurface. The inscriber rod 26 is then pivoted to a position at restagainst the pattern element 78. The chuck end 26 is then brought intoengagement with the drawing surface and the inscriber rod is moved in apath determined by the outline of the opening 80 for reproducing acorrespondingly shaped figure on the drawing surface. The rod 46 isspring tensioned so that its chuck end 26 is held in proper pressurerelationship with the drawing surface.

In reproducing pattern outlines lying in a predetermined angle to thehorizontal, the pointer I is swung to the right or the left and to thedesired degree mark on the scale i2, depending upon the direction ofangle desired, after which the pointer is made secure and the inscriberrod 28 manipulated in the same manner as when outlining horizontaloutlines. With a given set of pattern elements 18, each pattern may bereproduced in a large range of selected proportions, depending upon thevertical distance between the pattern element and the drawing surface24. In outlining relatively small patterns, a sleeve I32 is slipped overthe inscriber rod 26 to lie within the opening 8., thereby increasingthe diameter of the inscriber rod so as to produce a smaller outline.

I In reproducing patterns of relatively large outline, each of the legsi2, II and I6 is provided with an extension I34, which extension isproshort legs, while the scale I2. is employed when using the legextensions. The sleeve I82 is employed only when reproducing patternoutlines less than one inch in diameter for maximum length. The leg IIis provided with a pivoted pointer 2 which may be employed in certaintypes of drawing where it is desirable to locate the instrument on apredetermined line located at right angles to a second predeterminedline on which the fixation points of the legs l2 and H are located.

Without further elaboration, the foregoing will so fully illustrate myinvention, that others may, by applying current knowledge, readily adaptthe same for use under various conditions of service.

I claim:

1. A drafting instrument comprising a head having supporting legs, aninscribing rod depending from said head, a universal connection betweenthe upper end of the inscribing rod and said head, a pattern contourguide located to engage the inscribing rod intermediate its ends tocontrol its inscribing movement, extensions for said legs, and means forvarying the size of theinscribing rod at its point of engagement withthe pattern contour guide to vary the size of the pattern reproduced bythe inscribing rod.

2. A drafting instrument comprising a head having supporting legs, aninscribing rod having a universal connection with said head. a patterncontour guide located to engage the inscribing rod intermediate its endsto control its inscribing movement, a cradle fixedly related to saidhead, and pivot means on said cradle supporting said pattern contourguide for pivotal movement about a horizontal axis.

3. A drafting instrument comprising a headhaving supporting legs, aninscribing rod having a universal connection with said head, a patterncontour guide located to engage the inscribing rod intermediate its endsto control its inscribing movement, a ruler member slidably mounted onsaid head for vertical movement, a cradle attached to said ruler member,and first and second pivot means carried by said cradle for supportingsaid pattern contour guide for movement about a horizontal axis, saidfirst pivot means being threadedly connected with said cradle andadjustable for loosely or fixedly sup-V porting the pattern contourguide.

4. The invention described in claim 3 wherein said cradle is providedwith a scale, and a pointer attached to said second pivot means coactingwith said scale to denote the angular position of said pattern contourguide.

JESSIE T. IVY.

